Lecture #7 - Kreisle Flashcards
Five factors involved in capillary exchange.
Hydrostatic Pressure (BV and IS)
Colloid Osmotic Pressure (BV and IS)
Lymph Flow
Two ways of calculating capillary exchange
Vessel-Interstitium
Going Out - Coming In
Write out the version of the capillary exchange equation you hate.
Pressure = (Cap Hydro - Int. Hydro) - (Plasma Colloid - Interstitial Colloid)
Relatioship of Flow to... Pressure Gradient Diameter Compliance Viscosity
More Pressure - More Flow
More Diameter - More Flow (r^4)
More Compliance = Less Resistance - More Flow
More Viscosity - Less Flow
Equation for Vascular Resistance
(Art. Press. - Ven. Press.)/Flow
Relationship of viscosity to hematocrit
Correlated
Which receptors are activiated to generate resistance in arterioles?
alpha-1 and beta-2
Effect of atherosclerosis on compliance
Lowers It
Equation for Velocity of Blood
Flow/Area
basic Flow Equation
Q = Change in P / R
How does a tube becoming rigid influence flow and pressure?
Less Flow
More Pressure
Compliance Eq.
Vol/Pressure
Vessels with greatest cross sectional area?
Capillaries
Largest percentage of blood volume is where?
Veins
Largest blood velocity?
Aorta
Relationship of PP and Art. Compliance
More Arterial compliance decreases pulse pressure
When do you hear semilunar stenosis?
Systolic Ejection
Effects of TPR on Venous Resistance Curve
Decreased TPR – steeper
Increased TPR – Less steep
Main regulator of MAP?
Sympathetics
What is the Bayliss Hypothesis?
When smooth muscle is stretched, it will automatically contract, increasing resistance
Increased flow will do what to metabolites?
Flush them out of the tissue, allowing vasoconstriction
Who always gets blood first and 2nd?
Brain and heart
Who loses the most blood during exercise?
Splanchnics
How is renal bloodflow autoregulated?
Fast Myogenic Response
Tubuloglomerular Feedback
Who are the central sensors of Blood Flow?
Aortic Arch Baros.
Carotid Body
Natiuretic pep. product. in Atria
Peripheral sensor of bloodflow?
Juxtoglomerular
What do aortic arch baros do?
loss in pressure –> increased sympathetics
What is the bainbridge reflex?
High Central venous Pressure causes….
Inc. Heart Rate
Renal Vasodilation
What turns on Carotid Body and Aortic Chemoreceptors?
Low Pressure
Low O, High CO2, High H+
What does Carotid Body do when turned on?
Activate Sympathetics
Regulates Respiration
What causes vasovagal syncope?
Massive parasympathetic outflow and loss of sympathetic tone
Where are PS and Sym neurons of the medulla modulated?
Solitary Nuclues
What does Sympathetic Stim do?
Inc. HR
Contractility/Capacitance
BV
Controls blood flow
Baroreceptors of the Carotid Sinus sense…
High Pressure
What happens after sympathetics activate chromaffin cells?
Epinephrine/Nore. release
alpha 1 – vasoconstriction
beta 1 – heart
Three catecholeamine vasoconstrictors?
Norepinephrine (beta1 in heart, alpha1 in vessels)
Epinephrine (very low can turn on beta2 for dilation)
Dopamine (dilator low, constrictor high) (alpha1)
Greatest beta-1 activatior
Dobutamine
Physiological causes of fainting with vasovagal syncope.
Bradycardia + loss of sympathetic tone
Describe the process after BP drops
Carotid Sinus Senses the drop
CV centers of medulla activate
Suprarenal (RAA stim) and symp gang. activation
Inc. HR+Contractility and Vasoconstriction
Does baroreceptor reflex help with hypertension?
No – receptor adapts to new set point
What happens in your body when you stand up?
Venous pressure falls - Blood pools at feet
Decreased CO, Decreased MAP
Sympathetic Activation/Compensation
What is Shy-Drager syndrome?
Progressive disorder of CNS – Autonomic System Failure
First sign – orthostatic hypertension
Who senses when pressures are too high?
Right Atria
What does ANP do?
Vasodilator and Causes Na excretion
Two Effects of ADH
V1 – Vasoconstriction
V2 – H2O Reabs
Effects of Renin/Angiotensin?
Antidiuretic (via promoting Na reabs)
Vasoconstriction
Aldosterone causes….
Na retention, K loss
ADH also stimulates what non-kidney activity?
Thirst
Why use an ACE inhibitor?
Prevents the generation of Angiotensin II
Stops body from raising its own BP
Explain myogenic control of Blood Flow.
If smooth muscle is stretched, it responds by contracting
Explain metabolic control of BF.
Vasodilator metabolites open precapillary sphincters and vasodilate arterioles
Most important blood flow regulator for cerebrum?
Local Metabolites
What is Hyperemia?
Active increase in bloodbloow
Name the vasodilator inflammatory mediators and their origin.
Prostacyclin – EC
NO – EC
Histamine – Mast Cells
Bradykinin – Serum
Name the vasoconstrictor inflammatory mediators and their origin.
Thromboxanes – Platelets
Endothelin – EC
What are three roles of NO?
Vasodilation
Platelet Inhibition
PMN Adhesion Inhibitor
What inflammatory mediators from from arachadonic acids?
Prostacyclin (VasoDil) and Thromboxanes (VasoCon)
Difference between active and reactive hyperemia?
Active – Bloodflow is controlled by metabolic Activity
Reactive – Reacts to period of decreased bloodflow
Cause of reactive hyperemia?
Accumulation of vasodilators
Reduced Oxygen Tension
Nutrient Depletion
Unique response of lung vessels to hypoxia?
Vasoconstriction
Effects of Thromboxane A2? Ways to inhibit?
Platelet Aggregation and Vasoconstriction
Asprin
Most potent, long lasting vasoconstrictors?
Endothelins
ECE is used to make
ET-1 (Endothelin)
What receptors are bound when epinephrine vasodilates?
Beta-2 adrenergic
Why is it hard to classify serotonin in this way?
It does different things at different concentrations
Potential treatment for pulmonary hypertension?
Inhaled NO
Prostacyclin
Three most important vasoactive substances from the vascular endothelium?
Prostacyclin
NO
Endothelin
What factor is induced by low O levels?
VEGF
